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Microsoft Dynamics AX (Archived)

Reduction principle for Master plans/Forecast plans

Posted on by 2,720

Hi,

Please, I need to understand the option "Transactions-dynamic period" for the Reduction principle field, in the Forescast plans/Master plans form. This is the description I found in Technet:

Transactions - dynamic period – Forecast requirements are reduced by the actual order transactions that occur during the dynamic period. The dynamic period covers the current forecast dates and ends with the start of the next forecast. This method does not use or require a reduction key. When using this option:

      • If the forecast is reduced completely, the forecast requirements for the current forecast become 0.

      • If there is no future forecast, forecast requirements from the last forecast that was entered are reduced.

      • Time fences are included in the forecast reduction calculation.

      • Positive days are included in the forecast reduction calculation.

      • If actual order transactions are greater than the forecasted requirements, the remaining transactions are not forwarded to the next forecast period

I don't understand when, or in which cases should this option be selected

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  • Suggested answer
    guk1964 Profile Picture
    guk1964 10,877 on at
    RE: Reduction principle for Master plans/Forecast plans

    The method given at the start of the post seems to be what you need i.e .rather than reduce by a % of demand over time periods, you instead reduce the forecast by the amount of the actual orders received.

    All forecasts are wrong in principle (otherwise they would be orders)  the question is whether its the quantity that is wrong i.e. I know the period of the  forecast is December but the quantity is just a forecast  , or I know the quantity exactly - because I have agreed a contract but I don't know exactly when/at what rate the order will be called off.

    The question is then when will you decide to reconcile and what will you do with the difference? some products are seasonal  umbrellas/ice creams , others have more consistent demand and while there may be some stock build ups and rundowns in the supply chain week by week over a quart sales may be consistent and you may want to roll forward some unused forecast.

    Forecast are often a self fulfilling prophecy anyway -  if you don't forecast enough, then you will not be able to sell extra and your forecast will then be 100% , if you sell less than forecast then you may well cut costs/promote the time and reduce future forecast so over successive periods the forecast again looks accurate.

    The approach to use varies by item and  depends on many factors - shelf life, storage cost/space, lead time and ease of replenishment, competition, price elasticity, margins etc.

    Will you focus enough to fill up the factory  and then target sales and marketing  to sell it? Or will you make to order and only forecast components? Are margins high enough that you cannot afford to lose a sale> is the market bug enough that you can always sell all you can make if the price is right? re=tc

    That is the basis of sales and operations planning and Ax provides some useful features but like all erp system it has challenges - e,g if you forecast 1000 for the period and you take an order for 999 on the first day then is that part of the forecast or not? and who will decide? ... the order entry clerk?

    If you sold milk to babies two years ago and they are now 2 years older, and competitors have entered the market then  is the history projection useful?

    Is it more important to forecast capacity and utilization, or components, or  semi finished goods or end items- I should every item be forecasted? and with same level of precision? - does a forecast need to be 100% of expected demand or is it more prudent to forecast more to maximise sales or less to reduce risk?

    The set up options needed are much clearer after such an analysis and the purpose of some of the features provided also then becomes clearer.

  • Jefry Then Profile Picture
    Jefry Then 1,980 on at
    RE: Reduction principle for Master plans/Forecast plans

    Hi Mike,

    Have you got solution for your case? I have similar case with you. I've been testing several times and so far all I know is not carried over next weeks.

  • Community Member Profile Picture
    Community Member Microsoft Employee on at
    RE: Reduction principle for Master plans/Forecast plans

    Hi Fredrik,

    Seems you have some good knowledge on this subject.  I am trying to roll the reduction key over to the next couple of weeks. We have customers place orders three weeks in advance, so I'd like to not have the forecast place requirements in the system for these three weeks.  The issue I can't resolve is that the weeks seem to be static, and so I would have to update the reduction %'s every week when before MRP runs.

    Here is an example:

    Week 1:  Forecast is 100, but reduction is 100%

    - Sales Orders are for 200, so I have to build 200

    Week 2:  Forecast is 100, but reduction is 100%

    - Sales Orders are for 50, so I have to build 50

    Week 3:  Forecast is 100, but reduction is 100%

    - Sales Orders are for 150, so I have to build 150

    Week 4:  Forecast is 100, but reduction is 0%

    - Forecast is 100, so I have to plan for 100

    But let's say week 1 is over and MRP runs on the start of week 2...Will the logic for the first three weeks carry over into the next 3 weeks, or will I have to go and change the 3rd week (which used to be the 4th week) to have a reduction of 100%?

    Thanks,

    Mike

  • fgil12 Profile Picture
    fgil12 2,720 on at
    RE: Reduction principle for Master plans/Forecast plans

    Thanks Fredrik, this helped a lot.

  • Verified answer
    Fredrik Sætre Profile Picture
    Fredrik Sætre 12,644 on at
    RE: Reduction principle for Master plans/Forecast plans

    If you have orders being placed as far as your period, then this is good to use. It all depend on your turn over speed, lead times and period lengths. But if you want your actual sales orders to reduce the forecast within a planning period, then this should be used.

    Say you have a monthly forecast and period, and for July you forcast 60 pcs. At this point you also have 5 in order for 02.07 and 10 pcs for 14.07.

    These orders will be a part of the forcast then and the requirement for the period is 60 (5+10+remaining forcast of 45).

    If you had get an additional order at 07.07 for 50 pcs, your requirements are 65. The order surpassed the forcast.

    If you don't use the reduction principle, you would have a requirement for 125....

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